Instrumentation and method for creating an intervertebral space for receiving an implant

ABSTRACT

A surgical instrument set for use in spinal surgery for forming a substantially quadrilateral space in the spine for implanting a spinal implant at least in part into and at least in part across a disc space between adjacent vertebral bodies and methods of use are disclosed. The instrument set includes an extended guard for providing protected access to the disc space and the adjacent surfaces of the adjacent vertebral bodies, a guide insertable into the guard, and a bone removal device insertable into said guide.

This application claims benefit of Provisional application Ser. No.60/117,039 filed Jun. 25, 1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to intervertebral spinal surgery, andmore particularly to surgical instrumentation and to a method forcreating one or more spaces between adjacent vertebral bodies in whichthe space has a shape and vertebral surfaces adapted in size to receivean implant or implants to be implanted in the space, and the method ofimplanting those implants.

2. Description of the Prior Art

The spinal disc that resides between adjacent vertebral bodies maintainsthe spacing between those vertebral bodies and, in a healthy spine,allows for relative motion between the vertebrae. With disease and/ordegeneration a disc may become painful and/or mechanically insufficientwarranting surgical fusion across the affected disc. Where fusion isintended to occur between adjacent vertebral bodies of a patient'sspine, the surgeon typically prepares an opening at the site of theintended fusion by removing some or all of the disc material that existsbetween the adjacent vertebral bodies to be fused. Because the outermostlayers of bone of the vertebral endplate are relatively inert to newbone growth, the surgeon must work on the endplate to remove at leastthe outermost cell layers of bone to gain access to the blood-rich,vascular bone tissue within the vertebral body. In this manner, thevertebrae are prepared in a way that encourages new bone to grow onto orthrough an implant that is placed between the vertebrae. An implant orinsert may or may not promote fusion of the adjacent vertebral bodies,may be an artificial spinal disc, may permit surface ingrowth, and maybe made of bone or inert material, such as titanium. All of theseexamples and more are implants.

Present methods of forming this space between adjacent vertebraegenerally include the use of one or more of the following: hand heldbiting and grasping instruments known as rongeurs; drills and drillguides; rotating burrs driven by a motor; and osteotomes, chisels, andscraping implements. Surgeons often prefer a drilling technique due toits being ease, quick, and accurate. Sometimes the vertebral endplatemust be sacrificed as occurs when a drill is used to drill across thedisc space and deeper into the vertebrae than the thickness of theendplate. Such a surgical procedure is typically used to prepare a spacein the spine for an implant having a circular cross section andnecessarily results in the loss of the hardest and strongest bone tissueof the vertebrae, the endplate, and thereby robs the vertebrae of thatportion of its structure best suited to absorbing and supporting theloads placed on the spine by everyday activity. Where the surgeonchooses to forego drilling a large bore across the disc space in anattempt to preserve that good bone he must nevertheless use one of theabove instruments to work upon the endplates of the adjacent vertebraeto access the vascular, cancellous bone that is capable of participatingin the fusion and causing active bone growth, and also to attempt toobtain an appropriately shaped surface in the vertebral bodies toreceive the implant, which means and method are unreliable for thatpurpose.

There exists therefore a need for an improved surgical instrumentationand a related method for providing a space that is non-circular in crosssection, and preferably a substantially quadrilateral space across theheight of a disc space and into the adjacent surfaces of the adjacentvertebral bodies while taking advantage of the safe, easy, and accuratetechnique of boring or drilling into the spine to form a space and toshape the adjacent endplates to receive implants not typicallyassociated with boring techniques.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to permit theformation of a substantially quadrilateral space in a spine forinserting a spinal implant into a disc space between adjacent vertebralbodies.

Yet another object is to provide surgical instrumentation for preparingan interbody space to receive a spinal implant and a related method forworking upon vertebral body endplates adjacent a disc space useful inany region of the human spine, specifically, the cervical, dorsal, orlumbar regions.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in theappended claims.

To achieve the objects and in accordance with the purpose of theinvention, as embodied and broadly described herein, the inventioncomprises a surgical instrument set for use in spinal surgery forforming a substantially quadrilateral space in the spine for implantinga spinal implant into a disc space between adjacent vertebral bodies andthe methods for doing so.

An embodiment of the present invention includes an instrument setincluding a spinal marker for marking a location on the spine. Themarker has a shaft and a disc penetrating extension extending from theshaft for insertion into the disc space between adjacent vertebralbodies. The shaft may have any number of cross sections includingrectangular and circular. The marker preferably includes a shoulder forabutting against the exterior of the adjacent vertebral bodies. The discpenetrating extension of the marker preferably is tapered to facilitateinsertion into the disc space. The shaft of the marker has a proximalend and an opposite distal end oriented toward the spine. The shaft ofthe marker preferably includes a passage having a dye receiver at theproximal end of the shaft of the marker and at least one dye exit holeat the distal end of the shaft of the marker for marking the spine. Themarker preferably includes means for coupling to a syringe.

The instrument set includes a guard having an opening for providingprotected access to the disc space and the adjacent surfaces of thevertebral bodies adjacent the disc space and having a disc penetratingextension extending from the guard for insertion into the disc spacebetween the adjacent vertebral bodies and for bearing against theadjacent vertebral endplates of the adjacent vertebral bodies. The guardmay have two disc penetrating extensions extending from the guard anddiametrically opposed to each other. The disc penetrating extensionspreferably has a leading-edge that may include either of a pointed,tapered, radiused, chamfered, or wedge tipped shape to ease insertion ofthe extensions into the disc space. The guard preferably is adapted toconform at least in part to the exterior of the adjacent vertebralbodies. The guard may include a shoulder that conforms at least in partto the exterior of the adjacent vertebral bodies. The shoulderpreferably curves to correspond to the external curvature of theadjacent vertebral bodies. The guard may further include means forengaging the adjacent vertebral bodies when in use. The guard includes ahollow shaft adapted to allow access through the hollow shaft to thedisc space.

The instrument set further includes a guide for guiding a bone removaldevice. The guide has a shaft adapted for insertion into the guard. Theguide includes means for guiding the formation of the substantiallyquadrilateral space across the height of the disc space and into theadjacent surfaces of the adjacent vertebral bodies. The guiding meanspreferably includes a plurality of guide bores. The plurality of guidebores may overlap one another. The plurality of guide bores may includethree guide bores, and in particular may include a main guide bore andtwo secondary guide bores located to a side of the main guide bore. Themain guide bore and the two secondary guide bores preferably areoriented such that the bores formed in the spine through the main guidebore and the two secondary guide bores form a first hole pattern, whichwhen the guide is rotated 180 degrees and used to form a second holepattern, the overlapping first and second hole patterns form thesubstantially quadrilateral space.

Another embodiment of the present invention further includes a secondaryguide having a shaft adapted to be inserted into the guard. Thesecondary guide preferably includes means for guiding the formation of abore centrally oriented within the space to be formed. The centrallyoriented bore preferably contacts opposite sides of the substantiallyquadrilateral space to be formed.

The instrument set may also include a bone compactor having a shaftadapted for insertion into the guard. The shaft terminates in acompaction end. The compaction end preferably has an upper surface and alower surface that presses upon the adjacent vertebral endplates of theadjacent vertebral bodies. The compaction end preferably has either arectangular, trapezoid, or quadrilateral cross-section, or any othershape corresponding to the desired cross-section of the space to beformed in the spine. The compaction end may be any of beveled, radiused,or tapered to ease introduction of the bone compactor into the space.The bone compactor may have a trailing end having a dimension greaterthan the shaft to prevent over penetration of the bone compactor intothe guard. Alternatively, the instrument set may include a tool having asharpened leading end so as to formalize the flattening of the vertebralsurfaces.

An embodiment of the invention also comprises a method for creating asubstantially quadrilateral space in a spine for inserting a spinalimplant into a disc space between adjacent vertebral bodies, comprisingthe steps of: positioning a guard into contact with the adjacentvertebral bodies for protecting access to the disc space and theadjacent vertebral bodies; and boring, through the guard, a plurality ofbores across the disc space to form the substantially quadrilateralspace across the height of the disc space and generally into theadjacent surfaces of the adjacent vertebral bodies, rather than deepinto the vertebral bodies themselves.

An embodiment of the present invention may include the step of markingthe spine for guiding, by reference marks, the proper location of theguard. The step of marking preferably includes inserting a penetratingextension of a spinal marker into a central point of the disc spacebetween the adjacent vertebral bodies. An embodiment of the presentinvention includes the step of placing dye spots on the spine byinjecting the dye through openings in a shaft of the spinal marker. Thedepth of penetration of the marker into the disc space is controlled.

An embodiment of the method of the present invention includes the stepof distracting the disc space between adjacent vertebral bodies, and inparticular, the distracting step may include the step of inserting adistractor having a disc penetrating extension into the disc spacebetween adjacent vertebral bodies and against endplates of the adjacentvertebral bodies. The depth of penetration of the distractor into thedisc space is preferably controlled. The method may further include thestep of changing disc penetrating extensions of the distractor inaccordance with a desired distractor distance between adjacent vertebralbodies. The guard may be inserted over the distractor in the disc space,and then the distractor may be removed from within the guard.

The positioning step may include inserting at least one disc penetratingextension extending from the guard into the disc space between theadjacent vertebral bodies for bearing against endplates of the adjacentvertebral bodies. The insertion of the disc penetrating extension intothe disc space in one embodiment of the preferred invention distractsthe adjacent vertebral bodies. Another method of the present inventionfurther includes the step of controlling a depth of penetration of theextension into the disc space. Another embodiment of the presentinvention includes the step of engaging the guard with the adjacentvertebral bodies through prongs extending from the guard and into theadjacent vertebral bodies.

The boring step may include the sub-step of using a template inassociation with the guard. The template may be rotated 180 degreesalong its longitudinal axis. The boring step may include the sub-step ofusing either of a drill, mill, laser, burr, grinder, or other means tobore the plurality of bores. The plurality of bores may overlap. Theboring step may include forming at least three bores in the spine toform a first bore pattern, and in particular may include forming atleast a main bore and at least two secondary bores located to a side ofthe main bore. The main bore has a diameter that is preferably greaterthan a diameter of each of the two secondary bores. The main bore in thespine is preferably positioned to form a portion of three sides of thesubstantially quadrilateral space formed in the spine. Each of the twosecondary bores are preferably positioned to form a portion of twoadjacent sides of the substantially quadrilateral space formed in thespine. A second bore pattern having at least three bores in the spinemay be formed such that the first and second bore patterns defined thesubstantially quadrilateral space. The substantially quadrilateral spacemay be one of a substantially rectangular shape and a substantiallytrapezoidal shape. Further a central bore can be utilized to increasethe width of the space formed. The described “quadrilateral space” isdefined to cover a space that is actually a generally flat upper andflat lower surface having a height therebetween that is symmetrical fromside to side and that may be uniform from front to back or may be suchthat these opposed surfaces are in angular relationship to each otherfrom front to back; to the extent that the sides of the space arelocated within the disc space and not the bone of the vertebral bodiestheir specific shape is not important, and need not be planar.

Further the invention may comprise the step of inserting a multiplepassage drill guide into the guard to guide the formation of thosebores. The guide may be inserted into the guard for guiding the formingof the first bore pattern. The invention may further include the stepsof removing the guide from the guard, rotating the guide 180 degreesalong its longitudinal axis, reinserting the guide into the guard, andforming, through the plurality of openings in the guide, a second borepattern, the first and second bore patterns defining the substantiallyquadrilateral space. The invention may further include the step ofcontrolling the depth of penetration of the guide into the guard.

Yet another embodiment of the present invention includes the step ofcompressing outer edges of the substantially quadrilateral space. Thestep of compressing preferably includes inserting a compactor having acompaction end through the guard and into the substantiallyquadrilateral space formed in the spine. The step of compressing mayalso include inserting a bone chisel compactor having a sharpenedcutting edge for cutting bone. The depth of penetration of the compactorinto the disc space is preferably controlled. The step of compressingmay include the sub step of inserting a spinal implant through the guardand into the substantially quadrilateral space formed in the spine tocompress the outer edges on the substantially quadrilateral space.

Another embodiment of the present invention includes a surgical methodto prepare a segment of a human spine having a disc and two vertebraeadjacent the disc to receive an implant that, by way of example and notlimitation, may be for fusion between body portions of the adjacentvertebrae and through the space previously occupied by the disc, each ofthe adjacent vertebrae to be fused including a vertebral body having anendplate outer surface adjacent the disc space, and a subchondral zoneimmediately internal to each endplate, the method comprising:positioning a guard into contact with the adjacent vertebral bodies forprotecting access to the disc space and the adjacent vertebral bodies;and forming, through the guard, a plurality of bores to form asubstantially quadrilateral space in the spine across the height of thedisc space and into the adjacent endplates of the vertebrae adjacent thedisc space, the quadrilateral space being formed by the removal of atleast bone from at least the adjacent endplates as deep as with, andgenerally not deeper than, the subchondral zone of each of the adjacentendplates.

It is understood that both the foregoing general description and thefollowing detailed description are exemplary and exemplary only, and arenot restrictive of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate preferred embodiments of theinvention. Together with the description, they serve to explain theobjects, advantages and principles of the invention. In the drawings:

FIG. 1 is a leading end side perspective view of a midline spinal markerof the present invention;

FIG. 2 is a leading end view of the midline spinal marker of FIG. 1;

FIG. 2A is a cross-sectional view along lines X—X of FIG. 2;

FIG. 2B is a cross-sectional view along lines Y—Y of FIG. 2;

FIG. 3 is a trailing end side perspective view of the midline spinalmarker of the present invention being inserted at the anterior vertebralmidline into the disc space between adjacent vertebral bodies of asegment of the spine;

FIG. 4 is a cross-sectional view along lines 4—4 of FIG. 3 illustratingthe spinal marker inserted into the disc space between two adjacentvertebral bodies along the vertebral midline;

FIG. 5 is a leading end side perspective view of a spinal distractor ofthe present invention;

FIG. 5A is a cross-sectional view along line 5A—5A of FIG. 5;

FIG. 6 is a trailing end side perspective view of the distractor of FIG.5 with an impaction cap for driving the distractor into the disc spacelateral to the midline (identified by reference mark) between theadjacent vertebral bodies of the spine;

FIG. 7 is a cross-sectional view along line 7—7 of FIG. 6 showing thedistractor inserted in the disc space between the adjacent vertebralbodies on one side of the vertebral midline;

FIG. 8 is an exploded trailing end side perspective view of a guardproviding protected access to the disc space and the adjacent surfacesof the vertebral bodies and an impaction cap of the present invention;

FIG. 9 is a leading end side perspective view of the guard of FIG. 8;

FIG. 10 is an exploded trailing end side perspective view of the guardof FIG. 8 for insertion over the distractor of FIG. 5 shown inserted inthe disc space between two adjacent vertebral bodies and a correspondingimpaction cap for seating the guard into the disc space;

FIG. 11 is a cross-sectional view along lines 11—11 of FIG. 10 showingthe guard inserted over the distractor in the disc space between theadjacent vertebral bodies on one side of the vertebral midline;

FIG. 12 is a trailing end side perspective view of a guard positionedover the distractor and seated after impaction to the distractor by theimpaction cap into the disc space and adjacent vertebral bodies on oneside of the vertebral midline;

FIG. 12A is a longitudinal cross-sectional view along 12A—12A of FIG. 12illustrating the guard positioned over the distractor and seated afterimpaction to the distractor by the impaction cap into the disc space andadjacent vertebral bodies on one side of the vertebral midline;

FIG. 13 is a trailing end side perspective view of an extractioninstrument to remove the distractor from within the guard;

FIG. 14 is an exploded trailing end side perspective view of a drillguide (template) of the present invention for guiding a drill forinsertion into the guard;

FIG. 15 is a cross-sectional view along lines 15—15 of FIG. 14illustrating the guard of the present invention on one side of thevertebral midline;

FIG. 16 is an exploded trailing end side perspective view of the guardwith the guide and with a large drill bit and a small drill bit used toremove bone from the adjacent vertebral bodies;

FIG. 17 is a cross-sectional view along lines 17—17 of FIG. 16illustrating the guard, the large drill bit placed within the guide andextending into the disc space on one side of the vertebral midline;

FIG. 17A is a cross-sectional view through the leading end of the drillassembly in the spine along lines 17A—17A of FIG. 16 illustrating theguard, the large drill bit placed within the guide and extending intothe disc space on one side of the vertebral midline;

FIG. 18 is a diagrammatic representation of the hole pattern formed withthe guide and large and small drill bits of the present invention aftera first drilling, then rotating the guide 180° and performing a seconddrilling;

FIG. 19 is a leading end side perspective view of a bone compactor ofthe present invention;

FIG. 20 is an exploded trailing end side perspective view of thecompactor of FIG. 19 for insertion within the guard shown engaging thespine and inserted in the disc space between two adjacent vertebralbodies with an impaction cap for advancing the compactor into the discspace;

FIG. 21 is a cross-sectional view along lines 21—21 of FIG. 20illustrating the compactor placed within the guard inserted into thedisc space on one side of the vertebral midline;

FIG. 22A is a trailing end perspective view of a universal handleassembly of the present invention;

FIG. 22B is a leading end perspective view of the engagement mechanismof the handle of FIG. 22A shown in the locked position;

FIG. 22C is a leading end perspective view of the engagement mechanismof the handle of FIG. 22A shown in the unlocked position;

FIG. 23 is an exploded trailing end side perspective view of the guardin place with a handle for an implant driver and an implant forimplanting through the guard and into the space between the two adjacentvertebral bodies created by the instrumentation and method of thepresent invention;

FIG. 24 is a fragmentary leading end view of the implant driverinstrument of FIG. 23;

FIG. 25 is a cross-sectional view along lines 25—25 of FIG. 23illustrating the implant driver instrument and implant inserted throughthe guard and into the space created between the two adjacent vertebralbodies on one side of the vertebral midline;

FIG. 26 is an exploded side perspective view of the guard, an extractionadapter for engaging the guard and, and an extraction instrument forengaging the adapter and for extracting the guard;

FIG. 27 is a side perspective view of the operated segment of the spinewith the guard removed having a first implant inserted on one side ofthe midline and between and in part into the adjacent vertebral bodiesin the space created by the instrumentation and method of the presentinvention and with the guard inserted on the opposite side of thevertebral midline next to the implant;

FIG. 28 is a cross-sectional view along lines 28—28 of FIG. 27illustrating the implant positioned on one side of the vertebral midlinein the space created by the instrumentation and method the of thepresent invention and the guard inserted in the disc space on theopposite side of the vertebral midline and next to the implant;

FIG. 29 is an exploded side perspective view of a segment of the spineprepared to receive two implants with the instrumentation and method ofthe present invention;

FIG. 29A is a top perspective view of the lower vertebral body of thesegment of the spine of FIG. 29;

FIG. 30 is a trailing end perspective view of a spacer of the presentinvention;

FIG. 31 is a leading end perspective view of a spacer of the presentinvention;

FIG. 32 is a side elevational view of two adjacent vertebral bodies inlordosis with an implant inserted into a space created between twoadjacent vertebral bodies in which the created space has a lordoticconfiguration with an implant having parallel upper and lower surfacesmaintaining the angular relationship of the adjacent vertebral bodies;

FIG. 33 is a side elevational view of two adjacent vertebral bodies inlordosis with a lordotic implant placed between the two adjacentvertebral bodies in a space created between the two adjacent vertebralbodies;

FIG. 34 is an exploded trailing end side perspective view of a secondembodiment of the guard of the present invention for placement into asegment of the spine having a removable insertion end and an adapter anda handle assembly;

FIG. 35 is a side elevational view of the removable insertion end havingextended portions with an anatomical configuration;

FIG. 35A is a side elevational view of an alternative embodiment of aremovable insertion end;

FIG. 35B is a side elevational view of yet another alternativeembodiment of a removable insertion end;

FIG. 36 is a fragmentary view of the leading end of the guard of FIG.34;

FIG. 37 is an exploded trailing end side perspective view of the guardof FIG. 34 inserted in the disc space between two adjacent vertebralbodies for receiving a drill (template) guide of the present invention;

FIG. 38 is a cross-sectional view along lines 38—38 of FIG. 37illustrating the guard inserted into the disc space between two adjacentvertebral bodies on one side of the vertebral midline;

FIG. 39 is a trailing end side perspective view of the guard with thedrill guide inserted into the guard and with a large drill bit and asmall drill bit of the present invention used to remove bone from theadjacent vertebral bodies;

FIG. 40 is a trailing end side perspective view of the guard inserted onone side of the vertebral midline and into the disc space between twoadjacent vertebral bodies and a central bore guide of the presentinvention for insertion therein;

FIG. 41 is a trailing end side perspective view of the central boreguide inserted in the guard and the large drill and a handle assembly ofthe present invention;

FIG. 42 is a diagrammatic illustration of the hole pattern formed withthe guide and the large and small drill bits of the present invention;

FIG. 43 is a diagrammatic illustration of the hole pattern formed afterthe drill guide instrument is flipped 180 degrees and additional holesare drilled with the large and small drill bits of the presentinvention;

FIG. 44 is a diagrammatic illustration of the space created with thedrill guide method of FIG. 43, but where the space to be prepared iswider than in FIG. 43;

FIG. 45 is the configuration of the space created with the drill guideinstrument and the holes drilled as shown in FIG. 44;

FIG. 46 is a diagrammatic illustration of a hole drilled with a centralbore drill guide into the space of FIG. 45 of the present invention;

FIG. 47 is the configuration of the space created with the drill guideinstrument and central bore drill guide instrument of FIG. 46 of thepresent invention;

FIG. 48 is another diagrammatic illustration of a space created withmultiple holes drilled with a central bore drill guide in accordancewith the present invention to prepare a still wider space;

FIG. 49 is a perspective view of a spinal fusion implant oriented in aninitial insertion position and configured for clockwise rotation withinthe disc space, the top and bottom walls thereof being tapered relativeto one another for inducing angulation of the adjacent vertebral bodies;

FIG. 50 is a side perspective view of a vise adapted to hold the implantof FIG. 49 for loading the implant with fusion promoting substances; and

FIG. 51 is a side perspective view of the vise of FIG. 50 holding theimplant of FIG. 49.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference will now be made in detail to the present preferred embodimentof the invention, as illustrated in the accompanying drawings.

FIGS. 1-28 are generally directed to an embodiment of an instrument sethaving a rectangular cross-section for use in spinal surgery for forminga substantially quadrilateral space in the spine. FIGS. 34-41 aregenerally directed to another embodiment of the present inventionsurgical instrument set having a circular coss-section for forming asubstantially quadrilateral space in the spine. FIGS. 29, 29A, 32, 33,and 42-48 generally show the space formed in the spine by the instrumentsets of FIGS. 1-28 and 34-41 with implants for placement in the createdspace. FIGS. 49-51 generally show an implant and vise adapted to holdthe implant for loading the implant with fusion promoting substances. Aninstrument set for use in spinal surgery is used to form a substantiallyquadrilateral space in the spine for implanting a spinal implant into adisc space between adjacent vertebral bodies.

The anterior aspect (front) of the spine may be exposed either byopening a surgical incision large enough to allow direct visualizationor laproscopically with a small opening to allow instruments to beplaced through the body from outside the body for visualization throughan endoscope. The vertebral midline, which bisects the vertebral bodiesalong the longitudinal axis of the spinal column separating left fromright is identified by the surgeon. As shown in FIGS. 1-4, an exemplaryembodiment of a midline marker 100 of the present invention preferablyis used to create reference marks at the vertebral midline on the discmaterial and on the adjacent vertebral bodies in a segment of the spine.Marker 100 has a shaft 102 terminating in an insertion tip 104 having atapered leading edge 106 allowing it to be placed into a multitude ofdiscs having various heights. Tapered leading edge 106 facilitates theinsertion of marker 100 into the disc material contained in the discspace between two adjacent vertebral bodies. The juncture of shaft 102and insertion tip 104 of marker 100 forms a shoulder 108 for buttingagainst the anterior aspect of the adjacent vertebral bodies and thusprevents unwanted over penetration of insertion tip 104 into the discspace. Also located at shoulder 108 at the anterior aspect of shaft 102are a plurality of dye exit holes 110. Dye exit holes 110 are incommunication via a passage 112 with a syringe engaging well 114 locatedat a trailing end or proximal end 116 of shaft 102. Well 114 is adaptedto receive the tip of a syringe (not shown), or any other well-knowndevice for containing and injecting a dye into marker 100. A preferredmarker 100 has advantages over a needle due at least in part to having ashoulder for preventing over penetration of the disc space or having theability to provide multiple marks on the spine via multiple dye exitholes.

After marker 100 is inserted into the disc space, it may have itsposition confirmed radiographically to make sure that insertion tip 104is accurately positioned at the vertebral midline and to assess thedepth of the disc space relative to the known length of insertion tip104. After marker 100 is correctly placed at the vertebral midline, adye such as indigo carmine dye preferably is attached to marker 100 atwell 114 at proximal end 116 of shaft 102. With injection, the dye flowsthrough passage 112 within shaft 102 of marker 100 and exits dye exitholes 110 to create reference marks 118 at the vertebral midline on theadjacent vertebral bodies and on the disc material. The position ofreference marks 118 corresponds to dye exit holes 110 at the leading endor distal end 120 of shaft 102 of marker 100. Marker 100 is then removedfrom the disc space and reference marks 118 remain on the vertebralbodies and disc material. Reference marks 118 are visible to the surgeonand are used as alignment reference points in guiding instruments intothe spine.

As embodied herein, and as shown in FIGS. 5-7, an instrument set of thepresent invention may include a distractor 130 that urges two adjacentvertebral bodies apart and maintains the vertebral bodies in a selectedspacial relationship to each other. Distractor 130 comprises a shaft 132capable of receiving a graduated series of removable, partially hollowtips 134. The junction of shaft 132 and tip 134 forms a shoulder 136that abuts against the two adjacent vertebral bodies when tip 134 isinserted between the two adjacent vertebral bodies. Shoulder 136 ofshaft 132 preferably curves to correspond to the external curvature ofthe vertebral bodies adjacent the disc space in which distractor 130 isinserted. Tip 134 is preferably, but not requisitely, hollow tofacilitate insertion into the disc material and to avoid displacing itsown volume that might cause disc protrusion. Tip 134 has a height at itsdistal end of approximately 4-16 mm that increases to approximately 7-20mm at the junction of tip 134 with shoulder 136 of shaft 132 tofacilitate insertion of tip 134 into the disc space. When usedanteriorly, tip 134 is generally of a lesser height at the leading end.A length of approximately 15-30 mm is preferred for use from anterior toposterior. The length of tip 134 is preferably 15-42 mm for usetranslaterally. The increase in height along tip 134 also may be used toposition the two adjacent vertebral bodies in an angular spacialrelationship, such as to create lordosis. Shaft 132 is preferably hollowto reduce the overall weight of distractor 130.

A proximal end 138 of distractor 130 comprises an extraction head 140for coupling to an extraction instrument 150 described in detail below.While a preferred embodiment is shown, it is appreciated that a varietyof configurations at proximal end 138 of distractor 130 could beutilized for the intended purpose, including but not limited to,threads, key-ways that rotate and lock, male and female interlockingparts and the like without departing from the present teaching.Insertion of distractor 130 into the disc space preferably is guided byreference marks 118 created by marker 100. During insertion ofdistractor 130, shaft 132 of distractor 130 preferably is positioned toone side of the vertebral midline marked by reference marks 118.

Tip 134 of distractor 130 may be driven into the disc space by animpaction force imparted to distractor 130 through an impaction cap 160which couples to proximal end 138 of distractor 130 and prevents damageto end 138 of distractor 130. In yet another alternative embodiment, anadapter engages distractor removing engagement means and the adaptorengages at its opposite end to a “T” handle that can be utilized with orwithout a mallet to install or remove distractor 130, or any of theother instruments that at their trailing ends are similarly configured.The depth of insertion of tip 134 of distractor 130 into the disc spaceis sufficient to achieve the desired distraction and vertebral alignmentand is limited by shoulder 136 that abuts the two adjacent vertebralbodies to prevent any unwanted movement of tip 134 beyond the discspace.

As embodied herein, and as shown in FIGS. 8-11, an instrument set of thepresent invention may include a guard 170 having a hollow body 172 thatterminates in an insertion end 174 that preferably curves to correspondto the external curvature of the two adjacent vertebral bodies of thespine. Extending from insertion end 174 of guard 170 are a pair of discpenetrating extensions 176 that are diametrically opposite one anotheron the sides of guard 170. Each of extensions 176 preferably have awedged tip to facilitate insertion into the disc material between thetwo adjacent vertebral bodies. Extensions 176 have a height thatpreferably is less than the height of guard 170 such that a shoulder 178is formed at the distal end 180 of guard 170 in which shoulder 178functions as a depth limiting stop to prevent over penetration ofextension 176 into the disc space.

Preferably, protruding from insertion end 174 of guard 170 also is apair of prongs 182 for engaging the bone of the vertebral bodies. Prongs182 function to engage guard 170 to the two adjacent vertebral bodiesand to hold the two adjacent vertebral bodies in a selected spacialrelationship. A proximal end 184 of guard 170 is open to permitinsertion of instruments and implants into guard 170 as described indetail below. The internal opening of guard 170 is suitably dimensionedfor receiving distractor 130. For laproscopic use, proximal end 184 ofguard 170 can be attached to a laproscopic port allowing for the passageof instruments through the port and guard 170 while effecting a fluidand gas seal.

As embodied herein, and as shown in FIGS. 10 and 11, with distractor 130inserted between the two adjacent vertebral bodies, guard 170 slidablyengages proximal end 138 of distractor 130 and advances toward the spinewith distractor 130 functioning as a guide post for aligning guard 170.Guard 170 seats into position with an impaction force imparted ontoproximal end 184 of guard 170 via a large impaction cap 160. As shown inFIG. 12, impaction cap 160 has an internal configuration capable ofreceiving extraction head 140 of distractor 130 and has a shoulderportion 162 for abutting proximal end 184 of guard 170. Once extractionhead 140 contacts the internal part of impaction cap 160, guard 170 canno longer advance and thus serves as a depth limiting stop. Guard 170,like distractor 130 and the bone compactor can also be installed andremoved by use of the slap hammer, or an adaptor and mallet.

With particular reference to FIGS. 11, 12, and 12A, after guard 170seats against and engages the spine, extensions 176 are positioned inthe disc space at opposite sides of the insertion end of distractor 130.Extensions 176 serve to create or maintain a selected spacialrelationship of the two adjacent vertebral bodies and also serve asguards to keep the surgical procedure within the area between extensions176 and to prevent any unwanted movement of an instrument or implantoutside of the area between extensions 176.

In an alternative embodiment of the present invention, guard 170 may beinserted directly into the spine without recourse to the preliminary useof distractor 130. In that case, it is preferred that the leading end ofextensions 176 of guard 170 be configured so as to both facilitate theeasy introduction of guard 170 into the disc space, and so as to urgethe vertebral bodies apart into a distracted state. For this purpose,the most distal end of extensions 176 themselves would have a lesserheight than the remainder of extensions 176 and preferably a pointed,tapered, radiused, or chamfered shape. It should be recognized thatwhile the present instrument set provides means for identifying andachieving the optimal intervertebral distraction prior to the removal ofany bone, it also provides for adjusting it later in the procedure viagraduated spacer blocks and graduated guards having a variety ofheights. While it is believed that the predistraction of theintervertebral space prior to bone removal is desirable, it is notrequisite and it is anticipated that the present instrument set allowsfor the distraction of the intervertebral space later in the procedure,and/or by the insertion of the implant itself.

As shown in FIG. 13, once guard 170 is seated, distractor 130 preferablyis removed with an extraction instrument 150 which couples to extractionhead 140 and may be advanced away from the spine with slap-hammer styleadvancement or pulled with a handle which couples to an end ofextraction instrument 150.

As embodied herein, and as shown in FIGS. 14-18, an instrument set ofthe present invention may include a guide 190 for creating aquadrilateral space, or more particularly a rectangular space betweenthe two adjacent vertebral bodies. Guide 190 preferably has a large bore192 and two small bores 194 to one side of large bore 192. Guide 190 hasa shaft 196 terminating in an insertion end 198 that is inserted intoguard 170. Guide 190 also has a trailing end 200 that preferably has adimension greater than the inside opening of guard 170 that functions asa depth limiting stop to prevent further insertion of guide 190 intoguard 170.

With particular reference to FIGS. 17 and 17A, a large drill bit 210 isshown having a longitudinal shaft 212 terminating at one end in acutting portion 214 and having an engagement head 216 at the other endfor engaging a rotating device, such as a handle or a power drivenmotor. A trailing end 218 of large drill bit 210 also includes a stopmember 220 for abutting the surface of trailing end 200 of guide 190 toprevent unwanted over penetration of large drill bit 210 into the discspace. Large drill bit 210 is configured and dimensioned for placementthrough large bore 192 of guide 190.

Similarly, a small drill bit 230 terminates in a cutting end 232 and hasan engagement head 234 for engaging a rotating handle or rotating motor.A trailing end 236 of small drill bit 230 also has an enlarged portion238 for abutting the trailing end 200 of guide 190 to prevent unwantedover penetration of small drill bit 230 into the disc space.

In use, large drill bit 210 passes through large bore 192 in guide 190to position the cutting portion 214 into the disc space and then isrotated to remove bone from the endplates of the two adjacent vertebralbodies. Large and small drill bits 210, 230 can be turned by a “T”handle or preferably by use of a power drill. Similarly, small drill bit230 passes through small bores 194 of guide 190 to position cutting end232 into the disc space and then rotates to remove bone from theendplates of the adjacent vertebral bodies. As shown in FIG. 17,extensions 176 of guard 170 protect the unwanted movement of large andsmall drill bits 210, 230 in a lateral or transverse direction andconfine the drilling products so that they are evacuated by drill bits210, 230.

As shown in FIG. 18, the holes created with large drill bit 210 andsmall drill bit 230 form a pattern as indicated in solid lines in thedrawing.

After the first three holes have been drilled, guide 190 is removed fromwithin guard 170. Guide 190 then is rotated 180 degrees and reinsertedinto guard 170. Guide 190 now is oriented such that large bore 192 ispositioned over the area in which the small holes were previouslydrilled and small bores 194 are positioned over the area in which thelarge bore was previously drilled. The drilling procedure with largedrill bit 210 and small drill bit 230 is repeated to create a pattern ofholes as indicated by the dotted lines in FIG. 18. The result of thisdrilling procedure, is the removal of a portion of bone from theendplates of the adjacent vertebral bodies creating a spaceapproximating the configuration of a rectangle.

Although the drilling of the bone of the endplates creates a space witha configuration that approximates the shape of a rectangle, if desired aperfect rectangle may be obtained by use of a rectangular bonecompactor.

As shown in FIGS. 19-21, a box-shaped bone compactor 240 has a shaft 242terminating in a compaction end 244. Compaction end 244 of shaft 242 mayinclude beveled, radiused, or thinned edges to ease introduction.Compactor end 244 compresses any remaining boney protuberances into thevertebral bodies achieving a perfectly rectangular space. A trailing end246 of shaft 242 may include an extraction head 248 for coupling to anextraction instrument 150.

In a preferred embodiment, there is no fixed stop until approximately32-36 mm, so that a slotted and calibrated impaction cap 260 can be usedto predictably and adjustably insert compaction end 244 into theintervertebral space to the desired optimal depth. Alternatively,compactor 240 can have a fixed depth limiting means. As a furtheralternative, leading edges 250 of compactor 240 can be sharpened so thatit functions wholly or in part as a chisel to cut rather than compactthe bone. This is considered less desirable, though still workable, thanthe preferred compaction end 244 by which the density of the bone at theprepared recipient site is actually increased by the compaction process.

Compactor 240 is inserted into guard 170 and advanced by an impactionforce imparted to the trailing end 246 of compactor 240 by an impactioncap 260 similar to the impaction cap previously described above. Theadvancement of compaction end 244 of compactor 240 impacts the remainingportions of the bone that were not removed in the drilling steppreviously described into the vertebral bodies themselves.

As an alternative to compactor 240, trial size spacers 291 resemblingimplants 290 with either smooth or abraiding surfaces may be impactedinto the space to complete the flattening of the opposed bone surfaces.

As show in FIGS. 22A-C, a handle assembly 270 is shown for coupling tothe drilling instrumentation and other instruments of the presentinvention. Compactor 240 is removed from within guard 170 by coupling toextraction instrument 150 and advanced outside of guard 170 withextraction instrument 150 shown in FIGS. 13 and 26.

FIGS. 23-25 show a driver 280 for inserting an intervertebral implant290 into the created space between the two adjacent vertebral bodies.Driver 280 has a leading end 282 configured to cooperatively engage animplant 290. As shown in FIG. 24, driver 280 has a threaded portion 284and a non-threaded pin 286 extending from the leading end 282 forinsertion into corresponding openings in the trailing end of the implant290. Threaded portion 284 is rotatable by a knob 288 at the opposite endof driver 280 so as to threadably couple driver 280 to implant 290.Driver 280 has a handle coupling means 289 for coupling to handleassembly 270 for controlling driver 280.

After implant 290 is coupled to driver 280, implant 290 and leading end282 of driver 280 are inserted into guard 170 and advanced towards andinto the created space between the two adjacent vertebral bodies. Afterimplant 290 has been placed within the created space by use of the “T”handle with or without impaction of the slap hammer, or an adaptor and amallet, knob 288 of driver 280 is rotated to uncouple implant 290 fromdriver 280. Driver 280 then is removed from within guard 170 leavingimplant 290 inserted in the created space.

It is clearly anticipated that while the specific configuration of thepreferred ends has been described, that a variety of threaded andnon-threaded means for coupling implants 290 to driver 280 could in thealternative be employed without departing from the present inventiveconcept.

FIG. 26 shows guard 170 being removed from the disc space and from theadjacent vertebral bodies with extraction assembly 150 which couples toan extraction adapter 152 configured to fit within the proximal end 184of guard 170. Extraction adapter 152 is locked into place by aspring-biased butterfly member that fits into corresponding notches atthe proximal end 184 of guard 170. After extraction assembly 150 iscoupled to guard 170, extraction assembly 150 is advanced away from thespine with a slap-hammer style motion or any other suitable means toremove guard 170 from the spine. After guard 170 is removed, implant 290remains in place in the created space between the endplates of the twoadjacent vertebral bodies.

FIGS. 27 and 28 show that the procedure being repeated on the oppositeside of the vertebral midline. Distractor 130 and guard 170 are rotated180 degrees to conform to the curvature of the vertebral bodies on thesecond side of the vertebral midline. The above steps for the presentinvention are repeated for inserting guard 170 into position on theopposite side of the vertebral midline. As shown in FIG. 28, firstimplant 290 is positioned and remains within the created space betweenthe adjacent vertebral bodies and guard 170 is positioned on theopposite side of the vertebral midline to first implant 290.

As shown with implant 290 in FIG. 29 and a spacer block 291 in FIG. 31,either of implant 290 or spacer block 291 may be inserted in the spacecreated in the spine. As shown in FIGS. 30 and 31, spacer block 291 mayhave an external configuration similar to that of the implant, exceptthat it may be more or less solid. It is appreciated that spacer blocks291 and implants 290 may be wedged-shaped or rectangular so as to adjustthe angular relationship of the vertebral bodies to each other.

As shown in FIGS. 32 and 33, the instrumentation and method of thepresent invention may be used to create or maintain lordosis of thespine in at least two ways and to accept both generally rectangular andtrapezoidal implants. As shown in FIG. 32, the created space may beformed at an angle to the vertebral endplates, such that the planes ofthe top and bottom surface of the created space are in an angularrelationship to each other. The two adjacent vertebral bodies arepositioned in angular relationship to each other with the insertion ofimplant 290 having parallel upper and lower surfaces within the createdspace. The insertion of implant 290 into the angular space causes thevertebral bodies to be placed in an angular relationship.

FIGS. 32 and 33 show two adjacent vertebral bodies in a desired lordoticangular relationship. In FIG. 32, the space was created by means of theshape of extensions 176 on guard 170 during the drilling and compactionprocedure. A rectangular space was formed with more bone removedposteriorly than anteriorly in anticipation of receiving a generallyrectangular implant 290. This is a preferred stable configuration as thecompressive loads of the spine onto implant 290 are received generallyperpendicular to the surface (rather than on an angle that might urgethe implant forward or backwards). Additionally, once installed implant290 is blocked from further penetration by the wall of bone created bythe removal of the bone before it, and is blocked from backing outbecause the implant upper and lower surfaces would need to move againstthe inclined slanted surfaces of the vertebral bodies in order to moveand that would require significantly more energy than remaining in themore stable position of being fully installed.

For the space shown in FIG. 33, extensions 176 of guard 170 werepositioned between the vertebral bodies so that the adjacent vertebralsurfaces were generally parallel during the creation of the recipientspace. This was done in anticipation that the desirable lordosis wouldbe achieved by the use of an implant at least in part generallytrapezoidal in shape, or having upper and lower surfaces for engagingthe adjacent vertebral bodies, which surfaces are in a non-parallelangular relationship to each other.

While this is theoretically a less stable configuration than thatpreviously described, it offers the advantage that the amount of boneremoval is minimal but sufficient for its intended purpose and thethickness of the bone removed is more uniform in thickness.

As shown in FIG. 33 instead of creating an angular space, the createdspace may have parallel upper and lower surfaces. The two adjacentvertebral bodies are positioned in an angular relationship to each otherwith the insertion of an implant having upper and lower surfaces thatare angled toward each other.

FIGS. 34-41 show a second set of instrumentation similar to the first inthat it provides both for the creation of a generally rectangular ortrapezoidal space in a non-traumatic way and for the insertion of animplant through the same instrumentation, but differs in that the guardis generally cylindrical while the prior guard was generallyrectangular. A rectangular shape has less volume and space than acylindrical shape, which has no corners and is less expensive tomanufacture.

FIGS. 34-36 show a second embodiment of a guard of the presentinvention. Guard 370 has a hollow body 372 that terminates in aninsertion end 374, which is removably coupled to body 372. The distalend 380 of guard 370 is curved to correspond to the external curvatureof the two adjacent vertebral bodies the spine. Extending from theinsertion end 374 are a pair of extensions 376 in a diametricallyopposite position on the sides of the insertion end 374. Each of the twoextensions 376 have a suitable configuration to facilitate insertioninto the disc material between the two adjacent vertebral bodies. Asshown in FIG. 35, extensions 376 may have an “anatomic” configuration toconform to the contours of the vertebral endplates adjacent to the discspace in which guard 370 is to be inserted. Preferably, but notrequisite, also protruding from the insertion end 374 are a pair ofprongs 382 for engaging the bone of the adjacent vertebral bodies.Prongs 382 function cooperatively with extensions 376 to engage guard370 to the adjacent vertebral bodies and to hold the two adjacentvertebral bodies in a selected spacial relationship. The proximateportion of insertion end 374 may include a threaded portion forthreadably coupling to body 372 of guard 370. It is appreciated thatother coupling means are anticipated without departing from the scope ofthe present invention.

FIG. 36 shows body 372 having a collar 404 which has a thread to engagethe threaded portion of the removable insertion end 374. Guard 370provides the added advantage of having interchangeable removableinsertion ends 374 with different shaped extensions depending on thesurgical procedure being employed. For example, instead of having ananatomical configuration, the extensions may have a parallelconfiguration as shown in FIG. 35A or may have a wedged configuration asshown in FIG. 35B, so as to allow the surgeon to achieve the desiredangular relationship of the vertebral bodies to be fused.

Proximal end 384 of hollow guard 370 is open to permit the insertion ofother instruments and implants into the guard as described herein. Aswith the previously described guard, a closeable part may be connectedto the proximal end 384 of this guard for laproscopic use allowing forthe passing of instruments through guard 370 while providing for a gasand fluid seal.

Guard 370 is seated into the disc space and engaged to the spine bybeing manually advanced or by imparting an impaction force onto theproximal end 384 of guard 370. As shown in FIG. 34, an insertion andextraction handle assembly 270 is shown with a coupling member forengagement to proximal end 384 of guard 370.

As shown in FIG. 38, after guard 370 is properly seated and engaged tothe spine, extensions 376 are positioned in the disc space between thetwo adjacent vertebral bodies on one side of the vertebral midline.Extensions 376 serve to maintain the spacial relationship of the twoadjacent vertebral bodies and also serve as guards to maintain aninstrument or implant within the area between extensions 376 and toprevent any unwanted movement of an instrument or implant outside of thearea between extensions 376.

FIG. 37 shows a guide 390 for creating a rectangular space between thetwo adjacent vertebral bodies. Guide 390 comprises a large bore 392 andtwo small bores 394 to one side of large bore 392. Guide 390 has a shaft396 terminating in an insertion end 398 that is capable of beinginserted into guard 370 and has a trailing end 400 having a dimensiongreater than the inside opening of guard 370 so as to act as a depthlimiting stop to prevent further insertion of 390 guide into guard 370.Moreover, guide 390 is prevented from rotating within guard 370 by pins402, which fit into the corresponding grooves at the proximal end 384 ofthe guard 370.

FIG. 39 shows a large drill bit 410 and a small drill bit 430 configuredsimilarly to large and small drill bits 210, 230 described above withspecific reference to FIG. 16. In use large drill bit 410 is passedthrough large bore 392 in guide 390 to position cutting end 414 into thedisc space and is then rotated to remove bone from the endplates of thetwo adjacent vertebral bodies. Similarly, small drill bit 430 is passedthrough the small bores 394 of guide 390 to position cutting end 432into the disc space and then rotated to remove bone from the endplatesof the adjacent vertebral bodies.

As shown in FIG. 42, the holes created with large drill bit 410 andsmall drill bit 430 form a pattern as indicated in the dotted lines.After the first three holes have been drilled to provide a large hole Land two small holes S, guide 390 is removed from within guard 370 andguide 390 is rotated a 180 degrees and reinserted into guard 370. Guide390 is now oriented such that large bore 392 is positioned over the areain which the small holes S were drilled and small bores 394 arepositioned over the area in which the large hole L was drilled. Thedrilling procedure with large drill bit 410 and small drill bit 430 isrepeated to create a pattern of holes as indicated by the dotted linesin FIG. 43. As a result of this drilling procedure, a substantialportion of bone is removed from the endplates of the adjacent vertebralbodies creating a space approximating the configuration of a rectangle.

As shown in FIG. 40, as the central portion of the space created may nothave all of the bone removed from the drilling procedure through guide390, a central bore guide 500 may be inserted into guard 370. Centralbore guide 500 has a large bore 502 that is centrally placed, such thatwhen large drill bit 410 is passed through central bore guide 500, theportion of bone remaining in the central portion of the space beingcreated can be removed. As shown in FIG. 44, the use of central boreguide 500 may be of particular value in removing remaining bone whereguide 390 has a hole pattern that when reversed provides for a lesseramount of overlap of bores formed through large bore 392. FIG. 45 showsthe space created with the drilling procedure through FIG. 44. Centralhole C created with central bore guide 500 is shown in dotted line inFIG. 46.

As shown in FIG. 47, the space created with the drilling procedure withthe present invention results in a substantial portion of bone beingremoved from the endplates of the adjacent vertebral bodies creating aspace that more closely approximates the configuration of a rectangle.

FIG. 48 shows a space created with the drilling procedure of the presentinvention to prepare a still wider space with a template pattern for theguide having a hole pattern that uses an offset central drill guide todrill two additional large bores to remove additional bone to form thespace.

By way of example only, impacted implant 290 has been illustrated as onetype of implant that could be inserted into the opening formed in thespine by the various embodiments of instrumentation and methods of thepresent invention. By way of another example, without limitation to useof any other type of implant, a self-broaching, rotatable impactedimplant such as disclosed in U.S. application Ser. No. 09/429,628, whichis hereby incorporated by reference herein, could also be inserted intothe opening formed in the spine by the instrumentation and methodsdisclosed herein.

With reference to FIG. 49, an interbody spinal fusion implant isindicated generally as 600. The implant has a body 602 having aninsertion end 604, a trailing end 606, opposed side walls 608, andopposed upper and lower walls 610. Body 602 has a cross section withside walls 608 intersecting the upper and lower walls 610 at junctionsthat are preferably two diametrically opposed corners and twodiametrically opposed arcs. Fin-like projections 612 extend outwardlyfrom respective ones of upper and lower walls 610 and are adapted topenetrate the vertebral endplates of the adjacent vertebral bodies uponrotation of implant 600 while the upper and lower walls 610 support thevertebral endplates of those adjacent vertebral bodies. Body 602 ofimplant 600 preferably includes a hollow portion that may be accessedthrough a cap 614 that is preferably located on an end of implant 600.The hollow portion is adapted to contain fusion promoting materialincluding, but not limited to, bone, in any of its varied forms,hydroxyapatite, coral, bone morphogenetic proteins, genes coding for theproduction of bone, and agents with the ability to induce cells tobecome osteoblasts or to make bone.

As shown in FIGS. 50 and 51, a vise 700 has surfaces 702 adapted tocooperatively receive fins 612 and thereby cover the openings betweenfins 612. While holding implant 600 in vise 700 with cap 614 removedfrom implant 600, fusion promoting material may be compressively loadedinto implant 600. Fusion promoting material may be loaded into implant600 until the material is extruded from openings in side walls 608.

Having described certain preferred embodiments of the surgicalinstrument set of the present invention, the method for creating asubstantially quadrilateral space in a spine will now be described inmore detail. A method for creating a substantially quadrilateral spacein a spine for inserting a spinal implant into a disc space betweenadjacent vertebral bodies, comprises the steps of: positioning guard 170into contact with the adjacent vertebral bodies for protecting access tothe disc base and the adjacent vertebral bodies; and boring, throughguard 170, a plurality of bores across the disc space to form thesubstantially quadrilateral space across the height of the disc spaceand into the adjacent surfaces of the adjacent vertebral bodies.

The present invention may include the step of marking the spine forguiding, by reference marks, the proper location of guard 170. The stepof marking preferably includes inserting a penetrating extension of aspinal marker 100 into a central point of the disc space between theadjacent vertebral bodies. An embodiment of the present inventionincludes the step of placing dye spots on the spine by injecting the dyethrough openings in a shaft 102 of spinal marker 100. The depth ofpenetration of marker 100 into the disc space is controlled.

Yet another embodiment of the method of the present invention includesthe step of distracting the disc space between adjacent vertebralbodies, and in particular, the distracting step may include the step ofinserting a distractor 130 having a disc penetrating extension into thedisc space between adjacent vertebral bodies and against endplates ofthe adjacent vertebral bodies. The depth of penetration of distractor130 into the disc space is preferably controlled. The method may furtherinclude the step of changing disc penetrating extensions of distractor130 in accordance with a desired distractor distance between adjacentvertebral bodies. Guard 170 may be inserted over distractor 130 and thedisc space, and then distractor 130 may be removed from within guard170. The positioning step may include inserting at least one discpenetrating extension 176 extending from guard 170 into the disc spacebetween the adjacent vertebral bodies for bearing against endplates ofthe adjacent vertebral bodies. The insertion of disc penetratingextension 176 into the disc space in one embodiment of the preferredinvention distracts the adjacent vertebral bodies. Another method of thepresent invention further includes the step of controlling a depth ofpenetration of extension 176 into the disc space. Another embodiment ofthe present invention includes the step of engaging guard 170 with theadjacent vertebral bodies through prongs 182 extending from guard 170and into the adjacent vertebral bodies.

The boring step may include the sub-step of using a template inassociation with guard 170. The template may be rotated 180 degreesalong its longitudinal axis. The boring step may include the sub-step ofusing either of a drill, mill, laser, or grinder to bore the pluralityof bores. The plurality of bores may be overlapping, circular, or both.The boring step may include forming at least three bores in the spine toform a first bore pattern, and in particular may include forming atleast a main bore and at least two secondary bores located to a side ofthe main bore. The main bore has a diameter that is preferably greaterthan a diameter of each of the two secondary bores. The main bore in thespine is preferably positioned to form a portion of three sides of thesubstantially quadrilateral space formed in the spine. Each of the twosecondary bores are preferably positioned to form a portion of twoadjacent sides of the substantially quadrilateral space formed in thespine. A second bore pattern having at least three bores in the spinemay be formed such that the first and second bore patterns defined thesubstantially quadrilateral space. The substantially quadrilateral spacemay be one of a substantially rectangular shape and a substantiallytrapezoidal shape.

Further the invention may comprise the step of inserting a multiplepassage drill guide 190 into guard 170. Guide 190 may be inserted intoguard 170 for guiding the forming of the first bore pattern. Theinvention may further include the steps of removing guide 190 from guard170, rotating guided 190 one hundred-eighty degrees along itslongitudinal axis, reinserting guide 190 into guard 170, and forming,through the plurality of openings in guide 190, a second bore pattern,the first and second bore patterns defining the substantiallyquadrilateral space. The invention may further include the step ofcontrolling the depth of penetration of guide 190 into guard 170.

Another embodiment of the present invention includes the step of boringa centralized bore within the substantially quadrilateral space. Thecentralized bore preferably forms a portion of opposite sides of thesubstantially quadrilateral space. Further the invention may include thestep of inserting a secondary guide 500 into guard 170 and furtherforming, through an opening in secondary guide 500, a centralized borewithin the substantially quadrilateral space.

Yet another embodiment of the present invention includes the step ofcompressing outer edges of the substantially quadrilateral space. Thestep of compressing preferably includes inserting a compactor 240 havinga compaction end 244 through guard 170 and into the substantiallyquadrilateral space formed in the spine. The step of compressingpreferably includes inserting compactor 240 having compaction end 244having a sharpened cutting edge for cutting bone. The depth ofpenetration of compactor 240 into the disc space is preferablycontrolled. The step of compressing may include the sub step ofinserting a spinal implant through guard 170 and into the substantiallyquadrilateral space formed in the spine to compress the outer edges onthe substantially quadrilateral space.

Another embodiment of the present invention includes a surgical methodto prepare a segment of a human spine having a disc and two vertebralbodies adjacent the disc for fusion between body portions of theadjacent vertebral bodies and through the space previously occupied bythe disc, each of the adjacent vertebral bodies to be fused including avertebral body having an endplate outer surface adjacent the disc space,and a subchondral zone immediately internal to each endplate, the methodcomprising: positioning a guard 170 into contact with the adjacentvertebral bodies for protecting access to the disc space and theadjacent vertebral bodies; and forming, through guard 170, a pluralityof bores to form a substantially quadrilateral space in the spine acrossthe height of the disc space and into the adjacent endplates of thevertebral bodies adjacent the disc space, the quadrilateral space beingformed by the removal of at least bone from at least the adjacentendplates as deep as with, and generally not deeper than, thesubchondral zone of each of the adjacent endplates.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification beconsidered as exemplary only, and a true scope and spirit of theinvention being indicated by the following claims.

What is claimed is:
 1. A surgical instrument set for use in spinalsurgery for forming a substantially quadrilateral space in the spine forimplanting a spinal implant into a disc space between adjacent vertebralbodies, said surgical instrument set comprising: a guard having anopening for providing protected access to the disc space and theadjacent surfaces of the vertebral bodies adjacent the disc space andhaving a disc penetrating extension extending from said guard forinsertion into the disc space between the adjacent vertebral bodies andfor bearing against the adjacent vertebral endplates of the adjacentvertebral bodies; and a guide for guiding a bone removal device, saidguide having a shaft adapted to be inserted into said guard, said guideincluding means for guiding the formation of a substantiallyquadrilateral space across the height of the disc space and into theadjacent surfaces of the adjacent vertebral bodies.
 2. The instrumentset of claim 1, wherein said guiding means includes a plurality of guidebores.
 3. The instrument set of claim 2, wherein said plurality of guidebores overlap one another.
 4. The instrument set of claim 2, whereinsaid plurality of guide bores are circular.
 5. The instrument set ofclaim 2, wherein said plurality of guide bores includes three guidebores.
 6. The instrument set of claim 5, wherein said three guide boresinclude a main guide bore and two secondary guide bores located to aside of said main guide bore.
 7. The instrument set of claim 6, whereinsaid main guide bore has a diameter and said two secondary guide boreshave a diameter smaller than the diameter of the main guide bore.
 8. Theinstrument set of claim 7, wherein each of said two secondary guidebores are sized and oriented within said guide to guide the formation ofa bore substantially contacting two adjacent sides of the substantiallyquadrilateral space to be formed.
 9. The instrument set of claim 7,wherein said main guide bore is sized and oriented within said guide toguide the formation of a bore substantially contacting three sides ofthe substantially quadrilateral space to be formed.
 10. The instrumentset of claim 8, wherein each of said two secondary guide bores are sizedand oriented within said guide to guide the formation of a boresubstantially contacting two adjacent sides of the substantiallyquadrilateral space to be formed.
 11. The instrument set of claim 10,wherein said main guide bore and said two secondary guide bores areoriented such that the bores formed in the spine through said main guidebore and said two secondary guide bores form a first hole pattern whichwhen said guide is rotated 180 degrees and used to form a second holepattern the overlapping first and second hole patterns form thesubstantially quadrilateral space.
 12. The instrument set of claim 11,wherein the overlapping first and second hole patterns form one of asubstantially rectangular space and a substantially trapezoid space. 13.The instrument set of claim 1, wherein said guide includes means forpreventing over penetration of said guide into said guard.
 14. Theinstrument set of claim 13, wherein said preventing means is a trailingend of said guide having a dimension greater than said shaft of saidguide.
 15. The instrument set of claim 1, wherein said shaft of saidguide has one of a rectangular cross-section and a circularcross-section.
 16. The instrument set of claim 1, further comprising asecondary guide having a shaft adapted to be inserted into said guard,said secondary guide including means for guiding the formation of a borecentrally oriented within the space to be formed.
 17. The instrument setof claim 16, wherein the centrally oriented bore contacts opposite sidesof the substantially quadrilateral space to be formed.
 18. Theinstrument set of claim 1, further comprising a bone compactor having ashaft adapted to be inserted into said guard, said shaft terminating ina compaction end.
 19. The instrument set of claim 18, wherein saidcompaction end has an upper surface and a lower surface for pressingupon the adjacent vertebral endplates of the adjacent vertebral bodies.20. The instrument set of claim 19, wherein said compaction end has oneof a rectangular and trapezoid cross-section.
 21. The instrument set ofclaim 19, wherein said compaction end has a substantially quadrilateralcross-section.
 22. The instrument set of claim 18, wherein saidcompaction end is one of beveled, radiused, and tapered to easeintroduction of said bone compactor into the space.
 23. The instrumentset of claim 18, wherein said shaft of said bone compactor has atrailing end having a dimension greater than said shaft to prevent overpenetration of said bone compactor into said guard.
 24. The instrumentset of claim 18, wherein said shaft of said bone compactor has one of arectangular cross-section and a circular cross-section.
 25. Theinstrument set of claim 1, wherein said guard has two disc penetratingextensions extending from said guard and diametrically opposed to eachother.
 26. The instrument set of claim 25, wherein said disc penetratingextensions have a leading edge including one of a pointed, tapered,radiused, chamfered, and wedge tipped shape to ease insertion of saidextensions into the disc space.
 27. The instrument set of claim 1,wherein said guard is adapted to conform at least in part to theexterior of the adjacent vertebral bodies.
 28. The instrument set ofclaim 1, wherein said guard includes a shoulder adapted to conform atleast in part to the exterior of the adjacent vertebral bodies.
 29. Theinstrument set of claim 28, wherein said shoulder has a curvaturecorresponding to the external curvature of the adjacent vertebralbodies.
 30. The instrument set of claim 1, wherein said guard includesmeans for engaging the adjacent vertebral bodies when in use.
 31. Theinstrument set of claim 1, wherein said guard includes a hollow shaftadapted to allow access through said hollow shaft to the disc space. 32.The instrument set of claim 1, further comprising a distractor having abody and a disc penetrating extension extending from said body forinsertion into the disc space between adjacent vertebral bodies and forbearing against endplates of the adjacent vertebral bodies.
 33. Theinstrument set of claim 32, wherein said disc penetrating extension ishollow to facilitate insertion of said extension into the disc space.34. The instrument set of claim 32, wherein said distractor conforms atleast in part to the exterior of the adjacent vertebral bodies.
 35. Theinstrument set of claim 32, wherein said distractor includes a shoulderadapted to conform at least in part to the exterior of the adjacentvertebral bodies.
 36. The instrument set of claim 35, wherein saidshoulder has a curvature corresponding to the external curvature of theadjacent vertebral bodies.
 37. The instrument set of claim 32, whereinsaid distractor includes a shaft having one of a rectangularcross-section and a circular cross-section.
 38. The instrument set ofclaim 32, wherein said distractor includes an end for detachablyreceiving variously sized distractor tips.
 39. The instrument set ofclaim 38, wherein said distractor tips have chisel surfaces.
 40. Theinstrument set of claim 1, further comprising a spinal marker formarking a location on the spine, said marker having a shaft and a discpenetrating extension extending from said shaft for insertion into thedisc space between adjacent vertebral bodies.
 41. The instrument set ofclaim 40, wherein said marker includes a shaft having one of arectangular cross-section and a circular cross-section.
 42. Theinstrument set of claim 40, wherein said marker includes a shoulder forabutting against the exterior of the adjacent vertebral bodies.
 43. Theinstrument set of claim 40, wherein said disc penetrating extension ofsaid marker is tapered to facilitate insertion into the disc space. 44.The instrument set of claim 40, wherein said shaft of said marker has aproximal end and an opposite distal end oriented toward the spine, saidshaft of said marker having a passage having a dye receiver at theproximal end of said shaft of said marker and at least one dye exit holeat the distal end of said shaft of said marker for marking the spine.45. The instrument set of claim 44, wherein said marker includes meansfor coupling to a syringe.
 46. A method for creating a substantiallyquadrilateral space in a spine for inserting a spinal implant into adisc space between adjacent vertebral bodies, said method comprising thesteps of: positioning a guard into contact with the adjacent vertebralbodies for protecting access to the disc space and the adjacentvertebral bodies; and boring, through said guard, a plurality of boresacross the disc space to form said substantially quadrilateral spaceacross the height of the disc space and into the adjacent surfaces ofthe adjacent vertebral bodies.
 47. The method of claim 46, wherein theboring step includes the sub-step of using a template in associationwith said guard.
 48. The method of claim 47, wherein the boring stepincludes the sub-step of rotating said template 180 degrees along itsaxis.
 49. The method of claim 46, further comprising the step ofinserting a multiple passage drill guide into said guard.
 50. The methodof claim 46, wherein the boring step includes the sub-step of using oneof a drill, mill, laser, and grinder to bore the plurality of bores. 51.The method of claim 46, wherein the boring step includes the sub-step ofboring a plurality of overlapping bores.
 52. The method of claim 46,wherein the boring step further includes the sub-step of boring aplurality of circular bores in the spine.
 53. The method of claim 52,wherein the boring sub-step includes the sub-step of forming at leastthree bores in the spine to form a first bore pattern.
 54. The method ofclaim 53, wherein the forming sub-step includes forming at least a mainbore and at least two secondary bores located to a side of said mainbore.
 55. The method of claim 54, wherein the forming sub-step furtherincludes forming said main bore having a diameter greater than adiameter of each of said two secondary bores.
 56. The method of claim55, wherein the forming sub-step further includes the sub-step ofpositioning each of said two secondary bores to form a portion of twoadjacent sides of said substantially quadrilateral space formed in thespine.
 57. The method of claim 55, wherein the forming sub-step furtherincludes the sub-step of positioning said main bore in the spine to forma portion of three sides of said substantially quadrilateral spaceformed in the spine.
 58. The method of claim 57, wherein the formingsub-step further includes the sub-step of positioning each of said twosecondary bores to form a portion of two adjacent sides of saidsubstantially quadrilateral space formed in the spine.
 59. The method ofclaim 58, wherein the forming sub-step further includes the sub-step offorming at least three bores in the spine to form a second bore pattern,said first and second bore patterns defining said substantiallyquadrilateral space.
 60. The method of claim 59, wherein the sub-step offorming said first and second bore patterns include, forming saidsubstantially quadrilateral space into one of a substantiallyrectangular and a trapezoidal shape.
 61. The method of claim 58, whereinthe boring step further includes the sub-step of inserting a guide intosaid guard for guiding the forming of said first bore pattern, saidguide having a plurality of openings.
 62. The method of claim 61,further including the steps of removing said guide from said guard,rotating said guide 180 degrees along its longitudinal axis, reinsertingsaid guide into said guard, and forming, through said plurality ofopenings in said guide, a second bore pattern, said first and secondbore patterns defining said substantially quadrilateral space.
 63. Themethod of claim 62, wherein the sub-step of forming said first andsecond bore patterns include, forming said substantially quadrilateralspace into one of a substantially rectangular and a trapezoidal shape.64. The method of claim 61, further including the step of controlling adepth of penetration of said guide into said guard.
 65. The method ofclaim 61, further including the step of inserting a secondary guide intosaid guard and further forming, through an opening in said secondaryguide, a centralized bore within said substantially quadrilateral space.66. The method of claim 65, wherein said centralized bore forms aportion of opposite sides of said substantially quadrilateral space. 67.The method of claim 46, further including the step of boring acentralized bore within said substantially quadrilateral space.
 68. Themethod of claim 67, wherein said centralized bore forms a portion ofopposite sides of said substantially quadrilateral space.
 69. The methodof claim 46, further including the step of compressing outer edges ofsaid substantially quadrilateral space.
 70. The method of claim 69,wherein said step of compressing includes inserting a compactor having acompaction end through said guard and into said substantiallyquadrilateral space formed in the spine.
 71. The method of claim 70,further including the step of controlling a depth of penetration of saidcompactor into the disc space.
 72. The method of claim 69, wherein saidstep of compressing includes inserting a compactor having a compactionend having a sharpened cutting edge for cutting bone.
 73. The method ofclaim 69, wherein said step of compressing includes the sub-step ofinserting a spinal implant through said guard and into saidsubstantially quadrilateral space formed in the spine to compress saidouter edges of said substantially quadrilateral space.
 74. The method ofclaim 46 wherein the positioning step includes inserting at least onedisc penetrating extension extending from said guard into the disc spacebetween the adjacent vertebral bodies for bearing against endplates ofthe adjacent vertebral bodies.
 75. The method of claim 74, wherein saidinsertion of said disc penetrating extension into the disc spacedistracts the adjacent vertebral bodies.
 76. The method of claim 75,further including the step of controlling a depth of penetration of saidextension into the disc space.
 77. The method of claim 76, furtherincluding the step of engaging said guard with the adjacent vertebralbodies through prongs extending from said guard and into the adjacentvertebral bodies.
 78. The method of claim 46, further including the stepof distracting the disc space between adjacent vertebral bodies.
 79. Themethod of claim 78, wherein the step of distracting includes the step ofinserting a distractor having a disc penetrating extension into the discspace between adjacent vertebral bodies and against endplates of theadjacent vertebral bodies.
 80. The method of claim 79, further includingthe step of controlling a depth of penetration of said distractor intothe disc space.
 81. The method of claim 79, further including the stepof changing disc penetrating extensions of said distractor in accordancewith a desired distractor distance between adjacent vertebral bodies.82. The method of claim 79, further including the steps of insertingsaid guard over said distractor and disc space and removing saiddistractor.
 83. The method of claim 46, further including the step ofmarking the spine for guiding, by reference marks, a proper location ofsaid guard.
 84. The method of claim 83, wherein said step of markingincludes inserting a penetrating extension of a spinal marker into acentral point of the disc space between the adjacent vertebral bodies.85. The method of claim 84, further including the step of placing dyespots on the spine by injecting said dye through openings in a shaft ofsaid spinal marker.
 86. The method of claim 84, further including thestep of controlling a depth of penetration of said marker into the discspace.
 87. A method for creating a substantially quadrilateral space ina spine for inserting a spinal implant into a disc space betweenadjacent vertebral bodies, said method comprising the steps of:positioning a guard into contact with the adjacent vertebral bodies forprotecting access to the disc space and the adjacent vertebral bodies;boring, through said guard, a plurality of bores across the disc spaceto form said substantially quadrilateral space in the spine; andcompressing outer edges of said substantially quadrilateral space. 88.The method of claim 87, wherein the boring step includes the sub-step ofusing a template in association with said guard.
 89. The method of claim87, wherein the boring step includes the sub-step of using one of adrill, mill, laser, and grinder in boring the plurality of bores. 90.The method of claim 87, wherein the boring step further includes thesub-step of boring a plurality of overlapping bores in the spine. 91.The method of claim 87, wherein the boring sub-step includes thesub-step of forming at least three bores in the spine to form a firstthree bore pattern.
 92. The method of claim 91, wherein the formingsub-step includes forming at least a main bore and at least twosecondary bores located to a side of said main bore.
 93. The method ofclaim 92, wherein the forming sub-step further includes forming saidmain bore having a diameter greater than a diameter of each of said twosecondary bores.
 94. The method of claim 93, wherein the formingsub-step further includes the sub-step of positioning each of said twosecondary bores to form a portion of two adjacent sides of saidsubstantially quadrilateral space formed in the spine.
 95. The method ofclaim 93, wherein the forming sub-step further includes the sub-step ofpositioning said main bore in the spine to form a portion of three sidesof said substantially quadrilateral space formed in the spine.
 96. Themethod of claim 95, wherein the forming sub-step further includes thesub-step of positioning each of said two secondary bores to form aportion of two adjacent sides of said substantially quadrilateral spaceformed in the spine.
 97. The method of claim 96, wherein the formingsub-step further includes the sub-step of forming at least three boresin the spine to form a second bore pattern, said first and second borepatterns defining said substantially quadrilateral space.
 98. The methodof claim 97, wherein the sub-step of forming said first and second borepatterns include, forming said substantially quadrilateral space intoone of a substantially rectangular and a trapezoidal shape.
 99. Themethod of claim 96, wherein the boring step further includes thesub-step of inserting a guide into said guard for guiding the forming ofsaid first bore pattern, said guide having a plurality of openings. 100.The method of claim 99, further including the steps of removing saidguide from said guard, rotating said guide 180°, reinserting said guideinto said guard, and forming, through said plurality of openings in saidguide, a second bore pattern, said first and second bore patternsdefining said substantially quadrilateral space.
 101. The method ofclaim 100, wherein the sub-step of forming said first and second borepatterns include, forming said substantially quadrilateral space intoone of a substantially rectangular and a trapezoidal shape.
 102. Themethod of claim 99, further including the step of controlling a depth ofpenetration of said guide into said guard.
 103. The method of claim 99,further including the step of inserting a secondary guide into saidguard and further forming, through an opening in said secondary guide, acentralized bore within said substantially quadrilateral space.
 104. Themethod of claim 103, wherein said centralized bore forms a portion ofopposite sides of said substantially quadrilateral space.
 105. Themethod of claim 87, further including the step of boring a centralizedbore within said substantially quadrilateral space.
 106. The method ofclaim 105, wherein said centralized bore forms a portion of oppositesides of said substantially quadrilateral space.
 107. The method ofclaim 87, wherein said step of compressing includes inserting acompactor having a compaction end through said guard and into saidsubstantially quadrilateral space formed in the spine.
 108. The methodof claim 107, further including the step of controlling a depth ofpenetration of said compactor into the disc space.
 109. The method ofclaim 87, wherein the positioning step includes inserting at least onedisc penetrating extension extending from said guard into the disc spacebetween the adjacent vertebral bodies for bearing against endplates ofthe adjacent vertebral bodies.
 110. The method of claim 109, whereinsaid insertion of said disc penetrating extension into the disc spacedistracts the adjacent vertebral bodies.
 111. The method of claim 109,further including the step of controlling a depth of penetration of saidextension into the disc space.
 112. The method of claim 109, furtherincluding the step of engaging said guard with the adjacent vertebralbodies through prongs extending from said guard and into the adjacentvertebral bodies.
 113. The method of claim 87, further including thestep of distracting the disc space between adjacent vertebral bodies.114. The method of claim 113, wherein the step of distracting includesthe step of inserting a distractor having a disc penetrating extensioninto the disc space between adjacent vertebral bodies and againstendplates of the adjacent vertebral bodies.
 115. The method of claim114, further including the step of controlling a depth of penetration ofsaid distractor into the disc space.
 116. The method of claim 114,further including the step of changing disc penetrating extensions ofsaid distractor in accordance with a desired distractor distance betweenadjacent vertebral bodies.
 117. The method of claim 114, furtherincluding the steps of inserting said guard over said distractor anddisc space and removing said distractor.
 118. A surgical method toprepare a segment of a human spine having a disc and two vertebralbodies adjacent the disc for fusion between body portions of theadjacent vertebral bodies and through the space previously occupied bythe disc, each of the adjacent vertebral bodies to be fused including avertebral body having an endplate outer surface adjacent the disc space,and a subchondral zone immediately internal to each endplate, saidmethod comprising: positioning a guard into contact with the adjacentvertebral bodies for protecting access to the disc space and theadjacent vertebral bodies; and forming, through said guard, a pluralityof bores to form a substantially quadrilateral space in the spine acrossthe height of the disc space and into the adjacent endplates of thevertebral bodies adjacent the disc space, said quadrilateral space beingformed by the removal of at least bone from at least the adjacentendplates as deep as within, and generally not deeper than, thesubchondral zone of each of the adjacent endplates.
 119. A method forcreating a substantially quadrilateral space in a spine for inserting aspinal implant into a disc space between adjacent vertebral bodies, saidmethod comprising the steps of: orienting a template relative to theadjacent vertebral bodies into which the substantially quadrilateralspace is created; and boring, through said template, a plurality ofbores across the disc space to form said substantially quadrilateralspace across the height of the disc space and into the adjacent surfacesof the adjacent vertebral bodies.
 120. The method of claim 119, whereinthe boring step includes the sub-step of rotating said template 180degrees along its axis.
 121. The method of claim 119, wherein the boringstep includes the sub-step of using one of a drill, mill, laser, andgrinder to bore the plurality of bores.
 122. The method of claim 119,wherein the boring step includes the sub-step of boring a plurality ofoverlapping bores.
 123. The method of claim 122, wherein the boringsub-step includes the sub-step of forming at least three bores in thespine to form a first bore pattern.
 124. The method of claim 123,wherein the forming sub-step includes forming at least a main bore andat least two secondary bores located to a side of said main bore. 125.The method of claim 124, wherein the forming sub-step further includesforming said main bore having a diameter greater than a diameter of eachof said two secondary bores.
 126. The method of claim 125, wherein theforming sub-step further includes the sub-step of positioning said mainbore in the spine to form a portion of three sides of said substantiallyquadrilateral space formed in the spine.
 127. The method of claim 125,wherein the forming sub-step further includes the sub-step ofpositioning each of said two secondary bores to form a portion of twoadjacent sides of said substantially quadrilateral space formed in thespine.
 128. The method of claim 127, wherein the forming sub-stepfurther includes the sub-step of forming at least three bores in thespine to form a second bore pattern, said first and second bore patternsdefining said substantially quadrilateral space.
 129. The method ofclaim 128, wherein the sub-step of forming said first and second borepatterns include, forming said substantially quadrilateral space intoone of a substantially rectangular and a trapezoidal shape.